You can add your Facebook application to your page tab, this will make more users for your applications but the main benefit will be promotion of your page. You can have a custom landing page for your page by adding a beautifully created application and that will lead for increased likes.

Application side preparation:

Your application should be coded such a way that it has only allowed FBML tags. Facebook restricts some tabs to be used inside Facebook. e.g. fb:like , fb:login. You will get an invalid tag error when you will add it as a tab.